William "Billy" McCann appears in the Season 3 episode of Quantum Leap titled "Runaway". The part of Beth is played in the episode by Joseph Hacker.
About Billy[]
When the family Butchie Rickett, whom Dr. Samuel Beckett leaps into in 1964 gpes on a cross-country sight seeing vacation from Florida to the Wyoming Mountains his parent run into Billy, who's an old high school classmate of the elder Ricketts, and old friend of mom Emma, he's accompanied by his 14-year-old daughter Beth, who seems to take a liking to Butchie, as she asks him wryly, '"What grade are you in?".
Sam does his best to keep the pair, Billy and Emma, apart but they just keep running into each other and eventually, Hank becomes jealous and his controlling nature gets worse. Turns out that Hank had went off to college himself on a football scholarship but he got injured and dropped out of college. He's very proud of owning his own poultry factory and is intimidated by the old suitor's doctorate degree and more prestigious career as a professor. In fact, Hank is so torn with envy that he even confronts Hank and tells him "Just stay away from my wife!!" as Sam, as Butchie, is able to separate the two, keeping Hank from striking him.
When Beth goes missing after going off into the forest after another argument with Hank, Billy accompanies Sam, Hank, Emma's husband, Butchie, Alexandra, and his daughter as part of the search party as they find Emma dangling from the side of a cliff as Butchie, or Sam as, and Hank are able to rescue her, with Al and Ziggy's help, of course.